lib/got_lib_deltify.h

   1 /*
   2  * Copyright (c) 2020 Ori Bernstein
   3  * Copyright (c) 2021 Stefan Sperling <stsp@openbsd.org>
   4  *
   5  * Permission to use, copy, modify, and distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  16  */
  17
  18 struct got_delta_block {
  19         off_t           len;
  20         off_t           offset;
  21         uint32_t        hash;
  22 };
  23
  24 struct got_delta_table {
  25         struct got_delta_block  *blocks;
  26         int                     nblocks;
  27         int                     nalloc;
  28
  29         /*
  30          * Index for blocks.  offs[n] is zero when the slot is free,
  31          * otherwise it points to blocks[offs[n] - 1].
  32          */
  33         uint32_t                *offs;
  34         int                      len;
  35         int                      size;
  36 };
  37
  38 struct got_delta_instruction {
  39         int     copy;
  40         off_t   offset;
  41         off_t   len;
  42 };
  43
  44 enum {
  45         GOT_DELTIFY_MINCHUNK    = 32,
  46         GOT_DELTIFY_MAXCHUNK    = 8192,
  47         GOT_DELTIFY_SPLITMASK   = (1 << 8) - 1,
  48 };
  49
  50 const struct got_error *got_deltify_init(struct got_delta_table **dt, FILE *f,
  51     off_t fileoffset, off_t filesize, uint32_t seed);
  52 const struct got_error *got_deltify_init_mem(struct got_delta_table **dt,
  53     uint8_t *data, off_t fileoffset, off_t filesize, uint32_t seed);
  54 const struct got_error *got_deltify(struct got_delta_instruction **deltas,
  55     int *ndeltas, FILE *f, off_t fileoffset, off_t filesize, uint32_t seed,
  56     struct got_delta_table *dt, FILE *basefile, off_t basefile_offset0,
  57     off_t basefile_size);
  58 const struct got_error *got_deltify_file_mem(
  59     struct got_delta_instruction **deltas, int *ndeltas,
  60     FILE *f, off_t fileoffset, off_t filesize, uint32_t seed,
  61     struct got_delta_table *dt, uint8_t *basedata, off_t basefile_offset0,
  62     off_t basefile_size);
  63 const struct got_error *got_deltify_mem_file(
  64     struct got_delta_instruction **deltas, int *ndeltas,
  65     uint8_t *data, off_t fileoffset, off_t filesize, uint32_t seed,
  66     struct got_delta_table *dt, FILE *basefile, off_t basefile_offset0,
  67     off_t basefile_size);
  68 const struct got_error *got_deltify_mem_mem(
  69     struct got_delta_instruction **deltas, int *ndeltas,
  70     uint8_t *data, off_t fileoffset, off_t filesize, uint32_t seed,
  71     struct got_delta_table *dt, uint8_t *basedata, off_t basefile_offset0,
  72     off_t basefile_size);
  73 void got_deltify_free(struct got_delta_table *dt);